Washington was abuzz with speculation yesterday that President Obama’s top merger watchdog, Christine Varney, might be leaving her post after two years.

The whispers traveled from the Beltway to Silicon Valley, where Varney, who heads the Justice Department’s antitrust division, was rumored to be interviewing with tech companies.

But faster than you can say monopoly, the Justice Department moved to quash the speculation. A spokeswoman for Varney told The Post, “She’s not interviewing in Silicon Valley,” and said there was no truth to the story.

Obama nominated Varney as assistant attorney general in 2009, vowing to ramp up antitrust enforcement after decades of weak regulation. But consumer advocates complain that Varney has been far less aggressive than promised and has yet to sue to halt a single merger along the lines of the government’s landmark case against Microsoft.

The closest she came was this week, when the Justice Department threatened to sue Nasdaq OMX if it didn’t halt its hostile bid for rival exchange operator NYSE Euronext.

Meanwhile, there’s buzz that Varney could be speaking to Facebook, which was reportedly in talks with former White House Press Secretary Robert Gibbs about a role that might help it prepare for an IPO.

Tech giants Intel and Hewlett-Packard, along with private equity firm Silver Lake Partners, were also mentioned as possibilities.

In between stints with the Federal Communications Commission and the Clinton administration, Varney headed the Internet practice at the Hogan & Harsten law firm advising companies.

The speculation comes just days after FCC Commissioner Meredith Atwell Baker came under fire for taking a job at Comcast after approving its takeover of NBC Universal.